我想实现的数据处理是先让数据分别按照企业个体、国别、年份排列好，然后再根据企业个体、国别形成一组，计算组间年份的等差。
实现数据处理结果应如图：
数据如下：
input int year str12(Stkcd StkShortName) str21 Country str3 CountryCode
2018 "000005" "世纪星源" "印度尼西亚" "IDN"
2015 "000005" "世纪星源" "德国"          "DEU"
2015 "000005" "世纪星源" "德国"          "DEU"
2016 "000005" "世纪星源" "德国"          "DEU"
2017 "000005" "世纪星源" "德国"          "DEU"
2018 "000005" "世纪星源" "德国"          "DEU"
2008 "000039" "中集集团" "丹麦"          "DNK"
2009 "000039" "中集集团" "丹麦"          "DNK"
2010 "000039" "中集集团" "丹麦"          "DNK"
2011 "000039" "中集集团" "丹麦"          "DNK"
2012 "000039" "中集集团" "丹麦"          "DNK"
2013 "000039" "中集集团" "丹麦"          "DNK"
2014 "000039" "中集集团" "丹麦"          "DNK"
2015 "000039" "中集集团" "丹麦"          "DNK"
2016 "000039" "中集集团" "丹麦"          "DNK"
2017 "000039" "中集集团" "丹麦"          "DNK"
2008 "000039" "中集集团" "德国"          "DEU"
2009 "000039" "中集集团" "德国"          "DEU"
2010 "000039" "中集集团" "德国"          "DEU"
2011 "000039" "中集集团" "德国"          "DEU"
2012 "000039" "中集集团" "德国"          "DEU"
2012 "000039" "中集集团" "德国"          "DEU"
2013 "000039" "中集集团" "德国"          "DEU"
2013 "000039" "中集集团" "德国"          "DEU"
2013 "000039" "中集集团" "德国"          "DEU"
2014 "000039" "中集集团" "德国"          "DEU"
2014 "000039" "中集集团" "德国"          "DEU"
2014 "000039" "中集集团" "德国"          "DEU"
2015 "000039" "中集集团" "德国"          "DEU"
2015 "000039" "中集集团" "德国"          "DEU"
2015 "000039" "中集集团" "德国"          "DEU"
2016 "000039" "中集集团" "德国"          "DEU"
2016 "000039" "中集集团" "德国"          "DEU"
2016 "000039" "中集集团" "德国"          "DEU"
2017 "000039" "中集集团" "德国"          "DEU"
2017 "000039" "中集集团" "德国"          "DEU"
2017 "000039" "中集集团" "德国"          "DEU"
2018 "000039" "中集集团" "德国"          "DEU"
2019 "000039" "中集集团" "德国"          "DEU"
2010 "000039" "中集集团" "新加坡"       "SGP"
2010 "000039" "中集集团" "新加坡"       "SGP"
2010 "000039" "中集集团" "新加坡"       "SGP"
2011 "000039" "中集集团" "新加坡"       "SGP"
2011 "000039" "中集集团" "新加坡"       "SGP"
2011 "000039" "中集集团" "新加坡"       "SGP"
2012 "000039" "中集集团" "新加坡"       "SGP"
2012 "000039" "中集集团" "新加坡"       "SGP"
2012 "000039" "中集集团" "新加坡"       "SGP"
2013 "000039" "中集集团" "新加坡"       "SGP"
2013 "000039" "中集集团" "新加坡"       "SGP"
2013 "000039" "中集集团" "新加坡"       "SGP"
2014 "000039" "中集集团" "新加坡"       "SGP"
2014 "000039" "中集集团" "新加坡"       "SGP"
2014 "000039" "中集集团" "新加坡"       "SGP"
2014 "000039" "中集集团" "新加坡"       "SGP"
2015 "000039" "中集集团" "新加坡"       "SGP"
2015 "000039" "中集集团" "新加坡"       "SGP"
2015 "000039" "中集集团" "新加坡"       "SGP"
2015 "000039" "中集集团" "新加坡"       "SGP"
2016 "000039" "中集集团" "新加坡"       "SGP"
2016 "000039" "中集集团" "新加坡"       "SGP"
2016 "000039" "中集集团" "新加坡"       "SGP"
2016 "000039" "中集集团" "新加坡"       "SGP"
2017 "000039" "中集集团" "新加坡"       "SGP"
2017 "000039" "中集集团" "新加坡"       "SGP"
2017 "000039" "中集集团" "新加坡"       "SGP"
2017 "000039" "中集集团" "新加坡"       "SGP"
2018 "000039" "中集集团" "新加坡"       "SGP"
2018 "000039" "中集集团" "新加坡"       "SGP"
2018 "000039" "中集集团" "新加坡"       "SGP"
2019 "000039" "中集集团" "新加坡"       "SGP"
2019 "000039" "中集集团" "新加坡"       "SGP"
2019 "000039" "中集集团" "新加坡"       "SGP"
2007 "000039" "中集集团" "柬埔寨"       "KHM"
2008 "000039" "中集集团" "柬埔寨"       "KHM"
2006 "000039" "中集集团" "比利时"       "BEL"
2007 "000039" "中集集团" "比利时"       "BEL"
2008 "000039" "中集集团" "比利时"       "BEL"
2008 "000039" "中集集团" "比利时"       "BEL"
2008 "000039" "中集集团" "比利时"       "BEL"
2008 "000039" "中集集团" "比利时"       "BEL"
2008 "000039" "中集集团" "比利时"       "BEL"
2009 "000039" "中集集团" "比利时"       "BEL"
2009 "000039" "中集集团" "比利时"       "BEL"
2009 "000039" "中集集团" "比利时"       "BEL"
2009 "000039" "中集集团" "比利时"       "BEL"
2009 "000039" "中集集团" "比利时"       "BEL"
2010 "000039" "中集集团" "比利时"       "BEL"
2010 "000039" "中集集团" "比利时"       "BEL"
2010 "000039" "中集集团" "比利时"       "BEL"
2010 "000039" "中集集团" "比利时"       "BEL"
2010 "000039" "中集集团" "比利时"       "BEL"
2011 "000039" "中集集团" "比利时"       "BEL"
2011 "000039" "中集集团" "比利时"       "BEL"
2011 "000039" "中集集团" "比利时"       "BEL"
2011 "000039" "中集集团" "比利时"       "BEL"
2011 "000039" "中集集团" "比利时"       "BEL"
2012 "000039" "中集集团" "比利时"       "BEL"
2012 "000039" "中集集团" "比利时"       "BEL"
2012 "000039" "中集集团" "比利时"       "BEL"
end